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PubMed2002

Cost-effectiveness of the implantable cardioverter-defibrillator versus antiarrhythmic drugs in survivors of serious ventricular tachyarrhythmias: results of the Antiarrhythmics Versus Implantable Defibrillators (AVID) economic analysis substudy.

BACKGROUND: The implantable cardioverter-defibrillator (ICD) is an effective but expensive device. We used prospectively collected data from a large randomized clinical trial of secondary prevention of life-threatening ventricular arrhythmias to determine the cost-effectiveness of the ICD compared with antiarrhythmic drug (AAD) therapy, largely with amiodarone. METHODS AND RESULTS: Charges for initial and repeat hospitalizations, emergency room, and day surgery stays and the costs of antiarrhythmic drugs were collected on 1008 patients. Detailed records of all other medical encounters and expenses were collected on a subgroup of 237 patients. Regression models were then created to attribute these expenses to the rest of the patients. Charges were converted to 1997 costs using standard methods. Costs and life years were discounted at 3% per year. Three-year survival data from the Antiarrhythmics Versus Implantable Defibrillators trail were used to calculate the base-case cost-effectiveness (C/E) ratio. Six-year, twenty-year, and lifetime C/E ratios were also estimated. At 3 years, total costs were $71 421 for a patient taking AADs and $85 522 for a patient using an ICD, and the ICD provided a 0.21-year survival benefit over AAD treatment. The base-case C/E ratio was thus $66 677 per year of life saved by the ICD compared with AAD therapy (95% CI, $30 761 to $154 768). Six- and 20-year C/E ratios remained stable between $68 000 and $80 000 per year of life saved. CONCLUSIONS: The ICD is moderately cost-effective for secondary prevention of life-threatening ventricular arrhythmias, as judged from prospectively collected data in a randomized clinical trial.

Aged↗
PubMed1997

Modification of patient driving behavior after implantation of a cardioverter defibrillator.

Driving habits among recipients of ICDs have not been well characterized previously, yet such information may have implications for development of national policy. This study was undertaken to characterize driving behavior after defibrillator implantation in our patient population. From 1988-1993, 82 ICDs were implanted at the University of Florida. All patients received defibrillator teaching preoperatively and postoperatively with particular emphasis placed on driving restrictions. A standardized questionnaire was developed to ascertain driving behavior, compliance with restrictions, and occurrence of motor vehicle accidents following implantation. The patients were divided into two groups according to whether or not they had received a shock from their device since implantation. Group I patients did, and Group II patients did not. Fifty-two out of 82 (63%, Group I) patients had at least one shock. The remaining 30 patients had received no shocks. Mean age and gender were no different between the two groups. Mean time since implantation was 6 +/- 1.3 years in Group I, compared to 4 +/- 1.5 years in Group II (P = 0.001). Forty-seven out of 52 (90%) and 26 out of 30 (87%) in Groups I and II, respectively, resumed driving after defibrillator implantation. There was no difference in the amount of time that passed prior to resumption of driving. Group I patients drove more, 20.5 +/- 27 miles/day compared to patients in Group II, 8.3 +/- 9.7 miles/day (P = 0.02). No patient experienced device discharge during driving; likewise, no patient was involved in a motor vehicle accident secondary to their device firing. Sixty-seven out of 82 (82%) patients complied with the instructions they thought they heard; seven patients in Group I and eight patients in Group II deliberately did not follow our advice. The majority of patients do comply with physician instructions, although the instructions they remember are not always the instructions given. If a national policy is created to prohibit driving after ICD implantation, effective enforcement may be difficult.

Accidents, Traffic↗
PubMed2006

[Implantable cardioverter defibrillators in pediatric patients: results in a series of 33 cases].

UNLABELLED: Implantable defibrillator is the recognized treatment of sudden cardiac death. Miniaturization of the devices allows implantation in children. METHODS: This multicentric retrospective study analyzed data of 33 children aged 18 years and less who were implanted from 1990 to 2005. RESULTS: Age of patients are 10 to 18 years, 20 patients were implanted after a resuscitation of sudden death, 10 after a syncope, 2 after a ventricular tachycardia and 1 in a prophylactic way. Tachycardias on primary electrical disease are most frequent (46%). Hypertrophic cardiomyopathy accounts for 22%, DAVD for 14%, congenital cardiopathies for 12%. Seventeen patients received appropriate shocks and 14 patients had inappropriate shocks. There were two unexplained deaths. Five leads fractures and two device infections were noted. CONCLUSION: Implantable defibrillator is an effective treatment for children high-risk of sudden death. Occurrence of inappropriate shocks due to sinusal tachycardia, infections and leads fractures are frequent.

Adolescent↗
PubMed2002

[Failure in the functioning of an implanted automatic defibrillator due to pneumothorax occurring during its implantation ].

A 67-year-old man with chronic bronchitis and coronary artery disease was scheduled to receive an implantable cardioverter defibrillator (ICD) after an episode of sustained monomorphic ventricular tachycardia. During implantation through the left subclavian vein, oxygen saturation decreased to slightly below baseline. Nevertheless, the procedure continued, given that the patient experienced neither breathing difficulties nor pain. When the ICD failed to reverse ventricular fibrillation induced to test the device, an external defibrillator was used. At that point, left-sided pneumothorax was observed by x-ray. Air in the pleural cavity caused an increase in the defibrillation threshold. After insertion of a thoracic drain, the ICD implantation procedure was completed successfully.

Aged↗
PubMed2003

[Indications for implantable automatic defibrillators: critical analysis].

The implantable automatic defibrillator (IAD), invented in 1980, has revolutionised the management of patients with malignant ventricular arrhythmias resistant to medical treatment or ablation procedures. The number of devices implanted continues to increase in the industrialised countries and, based on the results of clinical trials, the indications for IAD are now well codified and increase as new clinical studies are published. However, the absolute number of implantations in France remains low (about 1200 to 2000, about 20 per million population) for a number of reasons: cost of IAD, absence of reimbursement by the health service which has restrained the implantation to public hospitals, and information of cardiologists for whom IAD may seem to be reserved for a few exceptional cases. Several factors suggest that the number of implantations will increase in the near future. First of all, the procedures of implantation have become much more simple due mainly to technical improvements. Then, the results of recent studies have validated prophylactic implantations of these devices in primary prevention in the post-infarction period (MADIT, MUSTT, MADIT II studies) and have demonstrated the superiority of IAD over antiarrhythmic drug therapy in terms of global survival in patients with severe ventricular arrhythmias (AVID, CIDS, CASH studies).

Arrhythmias, Cardiac↗
PubMed1995

Results of delivered therapy for VT or VF in patients with third-generation implantable cardioverter defibrillators.

Third-generation implantable cardioverter defibrillators (ICDs) offer tiered therapy and can provide significant advantage in the management of patients with life-threatening arrhythmias. Three different types of ICDs were implanted in 21 patients with ventricular tachycardia (VT) or ventricular fibrillation (VF). Arrhythmia presentation was VT (76%), VF (10%), or both (14%). The mean left ventricular ejection fraction for the group was 32.4 +/- 7%. No surgical mortality occurred. Prior to discharge individual EPS determined the final programmed settings of the ICDs. During a mean follow-up of 13 +/- 1.4 months (range 2-20) the overall patient survival was 85.7%. No sudden arrhythmic or cardiac death occurred. Twenty of 21 patients (95%) received therapy by their device. In 14 patients (67%) antitachycardia pacing (ATP) was programmed "on," 13 of which was self-adaptative autodecremental mode. There were 247 VT episodes, 231 of which were subjected to ATP with 97% success and 3% acceleration or failure. Low energy shocks reverted all other VT episodes. VF episodes were successfully reverted by a single shock (93%), two shocks (6%), or three shocks (1%). We conclude that ATP therapy of VT is successful in the large majority of episodes with rare failures, and that VF episodes are generally terminated by a single ICD shock.

Cardiac Pacing, Artificial↗
PubMed1995

Evaluating and improving the cost-effectiveness of the implantable cardioverter-defibrillator.

The implantable cardioverter defibrillator (ICD) is an expensive, widely used device for severe ventricular arrhythmias. Marginal cost-effectiveness analysis is a technique to examine the incremental cost of treatment strategy in relation to its effectiveness. In this study, we used this technique to analyze the cost-effectiveness of the ICD compared with that of electrophysiology (EP)-guided drug therapy and examined ways in which it may be improved. We analyzed Michigan Medicare discharge abstracts (1989 to 1992) and local physician visit, test, and ICD charges. Effectiveness was from 218 previously described patients with ICDs in whom the time of first event (first appropriate shock or death) was determined and presumed to represent "control" (EP-guided drug therapy) mortality. We assumed a 4-year life cycle for the ICD generator and 3.4% operative mortality and used a 5% discount to prevent value. Data were analyzed in a 1-month cycle Markov decision model over a 6-year horizon, and results were updated to 1993 dollars. ICD effectiveness was an increase in discounted mean life expectancy of 1.72 years. Cost-effectiveness was $31,100/year of life saved (YLS). Results were minimally or modestly sensitive to variations in preoperative mortality; resource use; consideration only of patients with ICDs who were receiving any antiarrhythmic drug or specifically amiodarone; and to a decrease in the percentage of first shocks that would equal death without the ICD until the assumed percentage decreased to < 38%. At ejection fraction of < 0.25 and > or = 0.25, cost-effectiveness was $44,000/YLS and $27,200/YLS, respectively, and without preimplant EP study was $18,100/ YLS.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Cost and length of hospital stay: comparisons between nonthoracotomy and epicardial techniques in patients receiving implantable cardioverter defibrillators.

Twenty-five patients with implantable cardioverter defibrillators (ICDs) implanted intrathoracically (group I) were compared with 25 patients who underwent implant using the nonthoracotomy approach (group II). All systems were implanted by the same medical team, in the same high volume implanting center. Indications for implantation were comparable in both groups. Patient characteristics were not statistically different with the exception of age (66-group I vs 71-group II; P < 0.05). Although left ventricular ejection fractions appeared to differ (32% vs 37%, respectively), this difference was not statistically significant (P = 0.06). ICD models used in group I were: Ventritex Cadence (16), Telectronics Guardian 4211 (2), Medtronic PCD (7); in group II they were: Ventritex Cadence (15), Guardian 4211 (2), and CPI 1600 (1). Total length of hospital stay was 16 +/- 6 days for group I versus 12 +/- 5 for group II (P < 0.05). Number of postoperative days in an intensive care unit was 3.2 +/- 2.8 for group I versus 0.5 +/- 0.6 for group II (P < 0.0001). Postoperative length of stay was 8.2 +/- 3.1 for group I versus 5.7 +/- 4.4 for group II (P < 0.001). Mean total hospital charges for the entire length of stay were $72,918 +/- $26,770 in group I versus $55,031 +/- $42,870 in group II, representing a mean reduction of 21% in global costs for group II patients. These data confirm that nonthoracotomy ICD implantation in an experienced center is associated with significantly shorter hospital stays, a virtual elimination of the need for postoperative intensive care, and globally lower total hospital costs. In addition, the presence of a statistically older population in group II does not negate these beneficial effects.

Aged↗
PubMed2006

Cigarette smoking and the risk of supraventricular and ventricular tachyarrhythmias in high-risk cardiac patients with implantable cardioverter defibrillators.

INTRODUCTION: Nicotine elevates serum catecholamine concentration and is therefore potentially arrhythmogenic. However, the effect of cigarette smoking on arrhythmic risk in coronary heart disease patients is not well established. METHODS AND RESULTS: The risk of appropriate and inappropriate defibrillator therapy by smoking status was analyzed in 717 patients who received an implantable cardioverter defibrillator (ICD) in the Multicenter Automatic Defibrillator Implantation Trial-II. Compared with patients who had quit smoking before study entry (past smokers) and patients who had never smoked (never smokers), patients who continued smoking (current smokers) were significantly younger and generally had more favorable baseline clinical characteristics. Despite this, the adjusted hazard ratio (HR) for appropriate ICD therapy for fast ventricular tachycardia (at heart rates >or=180 b.p.m) or ventricular fibrillation was highest among current smokers (HR = 2.11 [95% CI 1.11-3.99]) and intermediate among past smokers (HR = 1.57 [95% CI 0.95-2.58]), as compared with never smokers (P for trend = 0.02). Current smokers also exhibited a higher risk of inappropriate ICD shocks (HR = 2.93 [95% CI 1.30-6.63]) than past (HR = 1.91 [95% CI 0.97-3.77]) and never smokers (P for trend = 0.008). CONCLUSIONS: In patients with ischemic left ventricular dysfunction, continued cigarette smoking is associated with a significant increase in the risk of life-threatening ventricular tachyarrhythmias and inappropriate ICD shocks induced by rapid supraventricular arrhythmias. Our findings stress the importance of complete smoking cessation in this high-risk population.

Aged↗
PubMed2000

Patients with implantable cardioverter defibrillators: transition to home.

Implantable cardioverter defibrillators (ICD) are highly effective in the identification and termination of malignant ventricular tachycardia and fibrillation. It is anticipated that the number of patients receiving this device will increase because of major advancements in technology and the results of prospective controlled clinical trials. Major life changes occur after implantation of the device. Continued research is needed to identify concerns and needs of patients with ICDs and their families. Specific interventions must be tested to determine efficacy. Nurses must be able to provide education and psychologic support to assist patients in their successful transition to home.

Continuity of Patient Care↗
PubMed2000

Use of an implantable cardioverter defibrillator in a patient with two implanted neurostimulators for severe Parkinson's disease.

We report a patient with Parkinson's disease treated with two pectorally implanted neurostimulators (NSs) who presented with a life-threatening ventricular tachyarrhythmia in whom an abdominal ICD was implanted. Testing during implantation showed that the NS did not affect the bipolar sensing of the ICD, even when the NSs were set at a frequency of 130 pulses/s with an output of 5 V and pulse width of 0.21 ms in a bipolar and a unipolar configuration. The ICD shock, however, did affect both NSs: there was a reset to the output Off state and there was a reset of the electrode polarities.

Defibrillators, Implantable↗
PubMed1991

Does reception of appropriate shocks from the implantable cardioverter defibrillator affect survival?

The implantable cardioverter defibrillator has become an important therapeutic modality for treatment of life-threatening ventricular tachyarrhythmias. Recent reports have suggested that patients who receive appropriate shocks from this device have an inordinately high overall mortality, and questioned the extent of benefit these patients derive from the implant. This report analyzed the survival among 184 patients who received the implantable cardioverter defibrillator to assess survival differences between patients who received appropriate shocks versus those who did not. At a mean follow-up of 24 +/- 18.7 months, 68 patients received an appropriate shock from their device while 116 did not receive an appropriate shock. Overall survival of the entire population was quite similar to those published by others. There was no significant difference between overall survival of patients who received an appropriate shock versus those who did not. However, there was a statistically significant difference in sudden death mortality. The group of patients that received appropriate shocks included all five sudden deaths. This observation suggested that sudden death in this population was likely due to ventricular tachyarrhythmias rather than strictly bradycardia or asystole. The "benefit" of the device to the entire population was also assessed by estimating survival after receipt of the first appropriate shock. Using this approach, an estimated 10% of patients died without receiving an appropriate shock. In other words, ultimately, 90% of patients were expected to benefit from the device. This survival curve, which initiated only after receipt of the first appropriate shock was fairly similar to those estimated from conventional methods. Therefore, survival after receipt of an appropriate shock was comparable to overall survival and there was no significant difference between survival of patients who received appropriate shocks and those who did not.

Death, Sudden, Cardiac↗
PubMed1996

Reduction of antiarrhythmic drug use in patients receiving implantable cardioverter defibrillators.

Widespread use of implantable cardioverter defibrillators (ICDs) for the treatment of ventricular tachycardia (VT) and ventricular fibrillation (VF) occurred in the late 1980s and early 1990s. Additionally, there has been increasing appreciation during this time for both the lack of efficacy and proarrhythmic activity of antiarrhythmic drugs to treat these cardiac arrhythmias. We evaluated the use of antiarrhythmic drugs from 1987 to 1991 (5-year period) at the time of ICD implantation in 25,450 patients. The use of all classes of antiarrhythmic agents decreased from 61% to 24% during this time period (P < 0.05). In addition, there was a significant reduction in antiarrhythmic agent use for each drug class (P < 0.05) with the exception of Class II agents (beta blockers). These changes in drug use occurred independent of any changes in age, sex, ejection fraction, prevalence of coronary artery disease, or type of ventricular arrhythmia (VT vs VF).

Anti-Arrhythmia Agents↗
PubMed2005

Optimising the use of beta-adrenoceptor antagonists in coronary artery disease.

beta-Adrenoceptor antagonists (beta-blockers) provide multiple benefits to patients with coronary artery disease. The 2001 American Heart Association and American College of Cardiology (AHA/ACC) guidelines for secondary prevention of myocardial infarction (MI) recommend initiating beta-adrenoceptor blockade in all post-MI patients and continuing therapy indefinitely. Atenolol and metoprolol have been shown to decrease vascular mortality in the acute-MI period. In the post-MI period timolol provided a 39% reduction in mortality in the Norwegian Multicenter Study group and propranolol was associated with a 26% reduction in mortality in BHAT (Beta-blocker Heart Attack Trial). beta-Adrenoceptor antagonist therapy results in reduction of myocardial oxygen demand and is therefore also effective for the treatment of angina pectoris. In CAST (Cardiac Arrhythmia Suppression Trial) beta-adrenoceptor antagonist therapy was associated with a significant reduction in arrhythmic death or cardiac arrest. In the post-MI amiodarone trials EMIAT (European Myocardial Infarct Amiodarone Trial) and CAMIAT (Canadian Amiodarone Myocardial Infarction Trial) there was a mortality benefit and decreased arrhythmic death in patients who received both amiodarone and beta-adrenoceptor antagonist therapy, compared with patients receiving amiodarone therapy alone. In the post-MI defibrillator (implantable cardioverter defibrillator [ICD]) trials, AVID (Antiarrhythmic Versus Implantable Defibrillator) and MUSTT (Multicenter Unsustained Tachycardia Trial), beta-adrenoceptor antagonist therapy was independently associated with improved overall survival. The exception was the ICD patients in MUSTT, and the benefit was attenuated in the amiodarone and ICD patients in AVID.AHA/ACC guidelines recommend the use of beta-adrenoceptor antagonists in all patients with symptomatic left ventricular dysfunction, based on several large, controlled heart failure trials. Extended-release metoprolol succinate reduced all-cause mortality by 34% in MERIT-HF (Metoprolol Controlled-Release/Extended-Release Randomized Intervention Trial in Heart Failure). Bisoprolol was associated with a 34% mortality benefit in CIBIS-II (Cardiac Insufficiency Bisoprolol Study II) and carvedilol was associated with a 35% mortality reduction in the COPERNICUS (Carvedilol Prospective Randomized Cumulative Survival) trial. beta-Adrenoceptor antagonists reduce perioperative mortality in patients undergoing cardiac as well as non-cardiac surgery; however, they remain underutilised. Contraindications to beta-adrenoceptor antagonist therapy include severe bradycardia, high-grade atrioventricular block, marked sinus node dysfunction and acute exacerbations of heart failure. Many of the perceived adverse effects of beta-adrenoceptor antagonists have not been substantiated by large clinical trials.beta-Adrenoceptor antagonists differ with regard to receptor selectivity, receptor affinity, lipophilicity and intrinsic sympathomimetic activity. Beneficial properties of beta-adrenoceptor antagonists may not always be extrapolated as a class effect, and patient selection and drug preparations should follow trial guidelines. The beneficial effects of beta-adrenoceptor antagonists are clearly proven in cardiac patients and those at risk for cardiac disease. They are indicated for heart failure and proven beneficial in patients undergoing cardiac and non-cardiac surgery. These benefits appear to be consistent across most patient subgroups. beta-Adrenoceptor antagonists are generally well tolerated, yet significant morbidity and mortality result from their continued underutilisation.

Adrenergic beta-Antagonists↗
PubMed1998

The mean ventricular fibrillation cycle length: a potentially useful parameter for programming implantable cardioverter defibrillators.

In programming the implantable cardioverter defibrillator (ICD), the ventricular tachycardia (VT) detection cycle length (CL) is based on the CL of the documented tachycardia but the ventricular fibrillation (VF) detection CL is set arbitrarily. Appropriate programming of VF detection may not only reduce the incidence of inappropriate ICD shocks for non-VF rhythms but can also avoid the fatal underdetection of VF. The mean VFCL may provide a useful parameter for optimal ICD programming for VF detection if it is reproducible. This study examined the intrapatient reproducibility and interpatient variation of the mean VFCL in 30 ICD patients (25 men and 5 women, mean age 63 +/- 13 years). A total of 210 VF episodes (7 +/- 4 per patient, range 3-17) induced by T-wave shocks (166) or AC (44) at the ICD implant (30 patients) and the predischarge test (12 of 30 patients) were analyzed. The mean VFCL was calculated from the stored V-V intervals in the ICDs. Although the mean VFCL varied significantly from 171 +/- 6 to 263 +/- 11 ms (P < 0.01) among different patients, it was reproducible among different VF episodes in an individual patient (maximal variation 4-50 ms, P > 0.05). The mean VFCL was not significantly different between patients with and without antiarrhythmic drugs (210 +/- 32 vs 210 +/- 23 ms, P > 0.05) and was correlated with the ventricular effective refractory period (r = 0.5, P < 0.05). The mean VFCL varies greatly among different patients but remains reproducible in an individual patient, suggesting that the mean VFCL may serve as a reference for ICD programming of VF detection.

Adult↗
PubMed1992

Comparison of clinical benefits and outcome in patients with programmable and nonprogrammable implantable cardioverter defibrillators.

Technological advances in implantable cardioverter defibrillators (ICDs) have provided a variety of programmable parameters and antitachycardia therapies whose utility and impact on clinical outcome is presently unknown. ICDs have capabilities for cardioversion defibrillation alone (first generation ICDs), or in conjunction with demand ventricular pacing (second generation ICDs), or with demand pacing and antitachycardia pacing (third generation ICDs). We examined the pattern of antitachycardia therapy use and long-term survival in 110 patients with sustained ventricular tachycardia (VT) or ventricular fibrillation (VF). Group I included 62 patients with nonprogrammable first generation ICDs that delivered committed shock therapy after ventricular tachyarrhythmia detection based on electrogram rate and/or morphology was satisfied. Group II included 48 patients with multiprogrammable ICDs (including second and third generation ICDs) that had programmable tachyarrhythmia detection based on rate and tachycardia confirmation prior to delivery of electrical treatment with either programmable shocks and/or, as in the third generation ICDs, antitachycardia pacing. Incidence and patterns of antitachycardia therapy use and long-term survival were compared in the two groups. The incidence of appropriate shocks in patients who completed 1 year of follow-up was significantly greater in group I (30 of 43 patients = 70% vs 11 of 26 patients = 42%; P less than 0.05). In the total follow-up period, a significantly larger proportion of group I patients as compared to group II patients used the shock therapies (46 of 62 patients = 74% vs 25 of 48 patients = 52%; P less than 0.01), with the majority doing so within the first year of implantation (96% and 92%, respectively). Although the frequency of antitachycardia therapy activation was similar, the number of shocks delivered per patient was lower in group II, particularly in the initial 3 months of follow-up (P = 0.06). No clinical variable aided in identifying users from nonusers of antitachycardia therapy. Arrhythmic mortality was virtually eliminated in both groups. Two-year actuarial cardiac survival in the two groups was similar (group I = 78% vs group II = 84%; P greater than 0.2). Survival from cardiac mortality in users and nonusers of antitachycardia therapies was also similar in both groups (P greater than 0.2) and in the total patient group (P greater than 0.2). We conclude that programmable ICDs continue to confer advantages in prevention of sudden death that were observed with nonprogrammable ICDs and can be expected to improve patient tolerance and physician acceptance of device therapy for VT/VF.

Adult↗
PubMed2003

A randomized prospective study of single coil versus dual coil defibrillation in patients with ventricular arrhythmias undergoing implantable cardioverter defibrillator therapy.

ICD implantation is standard therapy for malignant ventricular arrhythmias. The advantage of dual and single coil defibrillator leads in the successful conversion of arrhythmias is unclear. This study compared the effectiveness of dual versus single coil defibrillation leads. The study was a prospective, multicenter, randomized study comparing a dual with a single coil defibrillation system as part of an ICD using an active pectoral electrode. Seventy-six patients (64 men, 12 women; age 61 +/- 11 years) were implanted with a dual (group 1, n = 38) or single coil lead system (group 2,n = 38). The patients represented a typical ICD cohort: 60% presented with ischemic cardiomyopathy as their primary cardiac disease, the mean left ventricular ejection fraction was 0.406 +/- 0.158. The primary tachyarrhythmia was monomorphic ventricular tachyarrhythmia in 52.6% patients and ventricular fibrillation in 38.4%. There was no significant difference in terms of P and R wave amplitudes, pacing thresholds, and lead impedance at implantation and follow-up in the two groups. There was similarly no difference in terms of defibrillation thresholds (DFT) at implantation. Patients in group 1 had an average DFT of 10.2 +/- 5.2 J compared to 10.3 +/- 4.1 J in Group 2, P = NS. This study demonstrates no significant advantage of a dual coil lead system over a single coil system in terms of lead values and defibrillation thresholds. This may have important bearing on the choice of lead systems when implanting ICDs.

Chi-Square Distribution↗